The present invention relates to a plant for producing products using a fluid, of the type comprising:                means for communicating with a source of the fluid;        means for delivering the fluid;        means for producing products associated with the means for delivering the fluid, in order to use the fluid in the production of products;        at least one device for purifying the fluid, placed between the communicating means and the delivery means; and        at least one sensor for the acquisition of purity information relating to the purity of the fluid downstream of the purification device.        
The invention applies, for example, to the production of food, pharmaceutical, parapharmaceutical, electronic, etc. products.
Many fluids, and especially gases (whether pure or a mixture), such as nitrogen, oxygen, carbon dioxide, nitrous oxide, argon, helium, hydrogen, etc., are used in the production of food products.
Such fluids may be used as technological auxiliary and are therefore not involved in or do not come into contact with finished food products at the time of their consumption. They are, for example, cryogenic fluids used to chill food products.
Such fluids may also be used as additives or as ingredients, and therefore remain in or in contact with the finished food products. These are, for example, fluids used as propellants or for forming protective atmospheres or for modifying the pH.
EP-932 007 discloses a plant for the filtration in liquid phase of a cryogenic fluid for removing microorganisms and/or physical particles. This plant does not include a sensor for the acquisition of information relating to the purity of the cryogenic fluid.
U.S. Pat. No. 4,759,848 discloses a plant for sterilizing a cryogenic liquid by filtration, and this plant also does not include a sensor for the acquisition of information relating to the purity of the filtered liquid.
FR-2 728 803 discloses a dry-air delivery system that includes means for purifying compressed air, but no sensor for acquisition of information relating to its purity.
WO-98/48259 discloses an in-line device for quantitatively and qualitatively differentiating between biotic and abiotic particles of a gas.
U.S. Pat. No. 5,428,555 discloses a system for obtaining and analyzing information relating to a process for producing semiconductor chips using a gas. That document does not mention the use of means for purifying the gas nor a sensor for the acquisition of information relating to the purity of the gas.
EP-584 747 discloses a plant of the aforementioned type that uses high-purity helium for the production of products. A purity measurement is carried out downstream of the purification devices that are connected in parallel and containing desiccants, adsorbents and/or oxidation catalysts. Such a measurement makes it possible to determine whether the helium must pass through one or other of the two devices, or through both of them, in order to ensure satisfactory purification.
However, the plant according to EP-584 747 does not provide proof that the manufactured products were manufactured in a safe manner, that is to say using helium of satisfactory purity, and no storage of the helium purification information is described.
It is an object of the invention to solve this problem by providing a plant of the aforementioned type that makes it possible to certify that the production of the products was carried out in a safe manner.
This is because it should be pointed out that although the quality of the gases delivered by the gas producer and/or supplier is usually guaranteed, on the other hand no guarantee or no systematic control of the quality of the gases from the chemical, physical and/or microbiological standpoint is provided at the point of use. The influence of the system on the quality of the gas is not monitored, and likewise the constancy over time of the quality of the gases at the point of use is not checked.
The generalized use of HACCP methods in food companies requires users to establish critical control points where risks (of a microbiological, physical or chemical nature) may arise. The quality of the gases at the point of use is therefore a critical point to be controlled within the context of this approach so as to ensure that the gas in contact with the food is not a source of contamination.
The object of the present invention is to formulate an overall approach for controlling and/or guaranteeing the quality of the gases or of the gas mixture from production to the point of use from the microbiological, physical and chemical standpoint.
It is preferable to include the setting up of measures for removing chemical, physical and/or microbiological contaminants at the point of use, the setting-up of a control system for checking the quality of the gases or of the gas mixture right up to the point of use, the setting-up of a continuous recording system for archiving the information (measurements, maintenance operations, failures) that occur along the gas delivery line and the setting-up of a traceability system for linking the delivery of the gases with the customer's production batches.